Typewriting machine



Nov. 7, 1939.

W. A. DOBSON TYPEWRITING MACHINE Filed Feb. 8, 1957 2 Sheets-Sheet 1 By Afforney WWW 4 [CM Nov. 7, 1939. w. A. DOBSON 2.178.682

TYPEWRITING MACHINE Filed Feb. 8, 1957 2 Sheets-Sheet 2 lNVENTOD ATTORNEY.

Patented Nov. 7, 1939 UNITED STATES PATENT OFFICE TYPEWRITING MACHINE Application February 8, 1937, Serial No. 124,541

6 Claims.

This invention relates to portable typewrlting machines and more particularly to the platencarriage supporting, shifting, and adjusting mechanism.

Desirable features of a portable typewriter are low-cost manufacture and compactness, and more particularly, small height, which produces a more conveniently carried package. It is important to maintain, as far as practicable, the salient characteristics of a standard typewriter such as a standard keyboard, case-shifting to upper and lower case positions, simple, positive, durable action, ease of assembly, and accessibility of adjustments.

In the present invention there are provided improved mountings and adjustments in a construction in which case-shifting involves pivotally mounting as a unit the platen, the platen carriage, the carriage anti-friction track, and the escapement mechanism. The pivotal mountings are in brackets which are mounted individually in either side of the typewriter frame for adjustment toward and away from the printing position of the type, and the carriage tracks are transversely adjustable with reference to the printing position of the type. The construction is simple and durable and permits of easy and facile assembly and disassembly, as well as adjustment of the various components. In one form the brack ets are mounted each on a plurality of feet adjustably mounted in parallel slots formed in opposite sides of the frame, other parallel slots permitting set screws to be passed therethrough into the brackets from the outside, the screws frictionally engaging the frame to lock the brackets. In a modification, each bracket has parallel sides which slide in parallel guides that are made integral with the frame by spot-welding.

The type-action is the subject-matter of my application, Serial Number 94,329, filed August 5, 1936.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a top view looking down from the rear with the side plates of the frame sectioned to show on the left the slot-adjustment of the bracket which pivotally mounts the carriage-andtrack supporting bar, and on the right a screw setting adjustment for the bracket.

Figure 2 is a side elevation partly in section and viewed from the right showing the tripod mounting of the case-shift supporting bracket, one of the case-shift pivots and the adjustment setting screws being indicated in dotted lines, a

case-shift stop plate, and a pair of stop screws therefor, the platen being in lower-case position, adjustable positions of the platen being shown in dot-and-dash lines.

Figure 3 is a side elevation partly in section, 5 broken out in the middle, and towards the front, and viewed from the right, but differing from Figure 2 in that the platen is in upper-case position, the lower-case position being shown in dot-' and-dash lines.

Figure 4 is a side view showing the adjustable mounting for the platen-carriage-support.

iFigure 5 is a sectional elevation of a modificat on.

A usual portable typewriter frame 20 has an ornamental cover 2| anda rear cross-piece 22 to which it is secured by screws 23. At the front a spacer rock-shaft 24 is mounted in and braces the sides of the frame and supports the usual spacer 25 by means of arms 26 secured on the 20 rock-shaft 24. Type-key levers, not shown, are mounted on a straight horizontal pivot rod 3| supported in a cross-piece 32 mounted in the frame 20 and which is provided with slots 33, the sides of which guide and support the key- 25 levers. Shift key-levers 34 are mounted at each side of the keyboard on the key-lever pivot rod 3|. Another cross-piece 35 secured in the sides of the frame 20 supports a pivot rod 36 on which shift-key sub-levers 41 are mounted. The shiftkey sub-levers 41 have parts of their rear edges formed as inwardly curved camming surfaces 38 which are engaged by side pins 39 mounted on the shift key-levers 34, the depression of these levers therefore swinging the sub-levers forwardly. The mentioned key levers actuate type actions which include links 40 pivotally connected to type bars 4| pivotally mounted on a type-bar segment rod 42, the latter being secured in a type-bar segment 43 mounted in the frame 20 40 by a bracket 44 at each end of the segment. The sub-levers 41 that are connected with the shift key-levers 34 carry links 45 for case-shifting the platen 54.

Case-shifting involves, in the present inven- 45 tion, tilting the platen 54 from the lower-case position shown in Figure 2 to the upper-case position shown in Figure 3. Each type-bar head 55 carries a lower-case type 56 and an uppercase type 51. The faces of the types 56, 51 may be curved concentrically with the curvature of the platen 54 and may be inclined to coincide with the planes tangent to the platen 54 at the respective printing points. Case-shifting of the platen 54 is effected by tilting a supporting cross- 55 bar 58 which has in either end a cylindrical bearing-pin 59, each of which has'in its outer end a slot 60 by which the pin 59 may be screwed into or out of the ends of the cross-bar 58.. The bearing surfaces of the pins 59 are spaced from the ends of the cross-bar 58 by spacing-washers 5I. The bearing-pins 59 are not supported directly in the sides of the typewriter frame 20 but instead are rotatably mounted in circular apertures in adjustable brackets 62. Clearance holes 63 substantially larger in diameter than the pins 59 may be formed in the sides of the frame 20, Figure 4.

Each bracket 82 is mounted for adjustment on a triangular or tripod arrangement of three feet 65 which are bent outwardly at right a'ngles to the plane of the bracket 62 and which are all in parallel with each other and the plane through a point exactly intermediate the upper and lower case type of any type-bar in the printing position and the axis of case-shift rotation. The feet 65 slide in slots 66 also in parallel with the feet 65, but formed in the sides of the frame 20. The tripod arrangement of feet 65 in the slots 66 assures a straight line adjustment of the brackets 62 towards and away from a mean printing position B. Set screws 61 pass through slots 68 formed in the sides of the frame 20 in parallel with the slots 66 and are fastened in the brackets 62. The top of the crossbar 58 has a downwardly and forwardly inclined top surface 69 on which is supported a forwardly inclined track-frame which has on either side upstanding flanges II. Each flange II has a right-angled groove or track extending crosswise of the machine and symmetrically opposed to the right-angled groove on the opposite flange II, the grooves providing tracks for anti-friction balls I2. A flat cross-piece I3 forms the base of the carriage or platen frame and has at the top and bottom right-angled flanges 14 forming tracks or grooves on their inner surface symmetrically opposed to each other and to the contiguous right-angled grooves of the flanges II, whereby the anti-friction balls I2 are secured rotatably between the flanges II and the flanges -14. The platen frame comprises vertical sidepieces 15 having at the bottom and rear inclined intumed flanges I6 which are secured at either end of the cross-plate 13 by screws I M and which rotatably support the platen 54, as is well known in the art. Slots 'l'I are formed transversely in the track-frame I0 and screws 18 pass through the slots into the inclined top 69 of the supporting cross-piece 58 and therefore permit of an ,upward and rearward and a forward and downward adjustment of the entire platen-carriagetrack-assembly.

Referring to Figures 2, 3 and 5 the dot-anddash lines A, B, and C represent planes intersecting the axis of the pivot pins 59 and the axis of the platen 54, when the platen is in lower case, intermediate, and upper case positions, respectively. The plane B is a plane equidistant from the planes A and C and adjustments are preferably made so that the plane B is parallel with the planes through the slots 66. Adjustment to true this plane may be made by means of the screw-slot adjustments I1, I8 and its operative position is precisely determined by the adjustment of screws I36 with reference to the depending stop-plate I34, as hereinafter further described.

A case-shift key-lever 34, sub-lever 41 and link 45, as shown in Figure 3, is provided on each side of the machine. Each of the case shift links 45 passes loosely through an aperture in the respective stop plates I 34,which plates are secured to the cross bar 58 adjacent the ends thereof. The links 45 each have an adjustment nut I33 threaded thereon and arranged to engage the rear of the plate I34. As the shift key lever 34 at either side of the machine is depressed, the corresponding link 45 is drawn forwardly by coaction of the case-shift sub-lever 41, and thereby tilts the cross bar 53 to effect case-shifting of the platen. Mounted on the brackets 62 are inwardly-turned ears I35, each supporting an adjustable stop screw I36. The screw I36 on the ears I35 of each bracket face each other and are disposed to be engaged by opposite sides of the case-shift stop-plate I34. Lock-nuts I'3'I on the screws I36 engage the outer walls of the ears I35 and lock the screws I36 in any adjusted position.

Referring to Figure 5 a modification is shown in which, in lieu of the bracket feet 65 and frame slots 66 for guiding the brackets 62, brackets I38 are provided having parallel straight side edges I44 at the bottom and I at the top, which engage parallel straight guide edges, the side edge I45 being more than twice the length of the side edge I44, and each edge extending on opposite sides of a line perpendicular to both side edges for reasons hereinafter explained. On the inside of the frame 20 an upper guide I39, having on its lower edge a straight guide edge I exactly parallel with and slidably engaging the upper guide edge I45 of a bracket I38, is spot-welded as indicated at I43 to the frame 20; and a lower guide I40, having on its upper edge a straight guide edge I42 exactly parallel with and slidably engaging the lower guide edge I44 of a bracket I38, is also spot-welded as indicated at I43 to the frame 20. The guides I39 and I40 are so positioned that the parallel guide edges I4I, I42 are parallel with and equidistant from the plane B through the axis of the pivot pin 59 and the point exactly equidistant from and intermediate a lower-case type 56 and an uppercase type 51.

The guides I39 and I40 extend in an overlapping position, that is, an upper portion of the guide edge I H and a lower portion of the guide edge I42 extend on opposite sides of a line perpendicular to both guide edges, I4I, I42. This overlapping relationship prevents excessive strain on the screws 61 when the platen 54 is shifted and has traveled about the pivots 59 into the upper-case position indicated in dot-and-dash lines at I46 in Figure 5, and the momentum may tend to rock the brackets I38 in a clockwise direction and press the bracket I38 against the upper part of the upper guide I39 and the lower part of the guide I40. Both guides I39 and I40 being spot-welded to the frame 20 so that the guides are virtually integral with the frame, any stresses set up in the guides are absorbed by substantial portions of the sides of the frame 20, thereby in a simple and low-cost device procuring a greatly increased factor of safety against any departure from parallelism in the guide edges I4I, I42. It is understood that this modification is of especial utility in a portable typewriter, which has a small height and a small front-to-rear dimension, and therefore necessarily a low side frame 20, this lowness of the side frame providing a limited space for opposed guides. This device requires in manufacture only a simple jig to locate the guides I38 and I40 accurately when spot-welded and slight attention to assure accurate width of the brackets I38 and exact parallelism of the edges 4, I45. Spot-welding enhances precision in setting the guides I39, I40 from a precision of a thousandth of an inch or more to a precision of a few tenths of a thousandth of an inch in the original setting and prevents variations even more in use by having two overlapping parallel guides spot-welded to an integral side of the frame to permanently secure the guides in the initial position.

The brackets I38 on opposite sides, like the brackets 62 on opposite sides, are separately and independently adjustable, which affords a simple mechanism for truing one end of the platen with reference to the other.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a typewriter, in combination, a frame having side walls, a type-bar mounted in the frame to strike downwardly and rearwardly on a platen, upper and lower case type on said typebar, a cylindrical platen, a carriage on which the platen is rotatably mounted, a track on which the carriage is reciprocated, a member having a forwardly inclined surface for supporting the platen-carriage and the track as a unit, pivots on opposite ends of the supporting member for swinging the platen to upper and lower case positions, two brackets each having a bearing for one of the pivots, each bracket having parallel rearwardly inclined sides, and guides mounted onthe inside of each side wall towards the rear, each guide having a straight edge engaging one of the rearwardly inclined sides.

' 2. In a typewriter, in combination, a frame having side walls, a type-bar mounted in the frame to strike downwardly and rearwardly on a platen, upper and lower case type on said type-bar, a cylindrical platen, a carriage on which the platen is rotatably mounted, a track on which the carriage is reciprocated, a member having a forwardly inclined surface for supporting the platencarriage and the track as a unit, pivots on opposite ends of the supporting member for swinging the platen to upper and lower case positions, two brackets each having a bearing for one of the pivots, each bracket having parallel rearwardly inclined sides, and guides mounted on the inside of each side wall towards the rear, each guide having a straight edge engaging one of the rearwardly inclined sides, each straight edge on one side extending on opposite sides of a line perpendicular to both of said straight edges to prevent excessive strain on locking screws, slots in each side wall parallel with the straight edges,

and locking screws mounted in said brackets and in said slots and engaging the outside of said side walls to lock the brackets in any adjusted position in said slots.

3. In a typewriter, in combination, a frame having side walls, a type-bar mounted in the frame to strike downwardly and rearwardly on a platen, upper and lower case type on said type bar, a cylindrical platen, a carriage on which the platen is rotatably mounted, a track on which the carriage is reciprocated, a member having a forwardly inclined surface for supporting the platen-carriage and the track as a unit, pivots on opposite ends of the supporting member for swinging the platen to upper and lower case positions, two brackets each having a bearing for one of the pivots, each bracket having parallel rearwardly inclined sides, and guides spot-welded on the inside of each side wall to make said guides integral with said side walls, each guide having a straight edge engaging one of the rearwardly inclined sides.

4. In a typewriter, in combination, a frame having side walls, a type-bar mounted in the frame to strike downwardly and rearwardly on a platen, upper and lower case type on said type-' bar, a cylindrical platen, a carriage on which the platen is rotatably mounted, a track on which the carriage is reciprocated, a member having a forwardly inclined surface for supporting the planten-carriage and the track as a unit, pivots on opposite ends of the supporting member for swinging the platen to upper and lower case positions, two brackets each having a bearing for one of the pivots, each bracket having parallel rearwardly inclined sides, and guides spot-welded on the inside of each side wall to make said guides integral with said side walls, each guide having a straight edge engaging one of the rearwardly inclined sides, each straight edge on one side extending on opposite sides of a line perpendicular to both of said straight. edges to prevent excessive strain on locking screws, slots in each side wall parallel with the straight edges, and locking screws mounted in said brackets and in said slots and engaging the outside of said side walls to lock the brackets in any adjusted position in said slots.

5. In a typewriter, in combination, a frame having side walls, a type-bar mounted in the frame to strike downwardly and rearwardly on a platen, upper and lower case type on said typebar, a cylindrical platen, a carriage on which the platen is rotatably mounted, a track on which the carriage is reciprocated, a member having a forwardly inclined surface for supporting the platen-carriage and the track as a unit, pivots on opposite ends of the supporting member for swinging the platen to upper and lower case positions, two brackets each having a bearing for one of the pivots, each bracket having parallel rearwardly inclined sides, and guides mounted on the inside of each side wall towards the rear, each guide having a straight edge engaging one of the rearwardly inclined sides, each straight edge on one side extending on opposite sides of a line perpendicular to both of said straight edges to prevent excessive strain on looking screws, the

straight edges being equidistant from the adjacent pivot mounting for the platen and the mean printing position of an upper and a lower case type, slots in each side wall parallel with the straight edges, and locking screws mounted in said brackets and in said slots and engaging the outside of said side walls to lock the brackets in any adjusted position in said slots. 7

6. In a typewriter, in combination, a frame having side walls, a cylindrical platen, a type-bar mounted in the frame to strike downwardly and rearwardly on said platen, upper and lower case type on said type-bar, a carriage on which the platen is rotatably mounted, a track on which the carriage is reciprocated, a member having a forwardly inclined surface for supporting the track and the platen-carriage as a unit, pivots on opposite ends of the supporting member for swinging the platen to upper and lower case positions, two brackets each having a bearing for one of the pivots, each bracket having parallel rearwardly inclined sides, guides on the inside of each side wall towards the rear, each guide engaging one of the rearwardly inclined bracket sides, siots in each side wall parallel with the guides, and locking screws mounted in said brackets and in said slots and engaging the outside of said side walls to lock the brackets in 5 any adjusted position in said slots, the brackets being independently and slidably mounted, by

means of said guides, for movement substantially WILLIAM A. DoBson. 

